Lock-up torque converter with damper

ABSTRACT

A lock-up torque converter comprises a torque converter assembly and a lock-up clutch, wherein the clutch provides a direct drive between the engine and transmission of a vehicle in high gear. A damper is located in a limited space between a clutch piston and a turbine runner to provide a driving connection. The damper includes a portion secured to an outer shell of the turbine runner, such as by welding.

BACKGROUND OF THE INVENTION

The present invention relates to a lock-up torque converter and moreparticularly to a compact arrangement of a damper which provides adriving connection between a lock-up clutch piston and a turbine runner.

A vehicle installed with a torque converter will show a poor fueleconomy because of the fact that any fluid coupling experiences somedegree of slip. A various kinds of lock-up torque converters have beenproposed in which a torque converter locks up by means of a built-inclutch in a predetermined (high speed) operating range of a vehicle whentorque variation of an engine is not experienced as a problem.

In a known lock-up torque converter, a damper for providing a drivingconnection between a clutch piston and a turbine runner is located in aspace available between an outer periphery of the clutch piston and anouter periphery of the turbine runner and it is drivably connected at aninlet element thereof to the clutch piston and at an outlet elementthereof to the turbine runner.

A problem with this damper arrangement is that since the damper isspaced radially outwardly from the axis of rotation about which theclutch piston and the turbine runner rotate by a considerable amount,the damper is thrown outwardly with such a large centrifugal force as toinduce malfunction of the damper when the vehicle operates at highspeeds.

In another known lock-up torque converter, a damper is located betweenan inner periphery of a clutch piston and an inner periphery of aturbine runner.

A problem with this known arrangement is that since the damper is spacedradially outwardly from the rotation axis by a relatively small amountas compared to the damper arrangement mentioned before, a large damperhas to be provided so as to afford to carry or transmit a large amountof torque and it requires complicated construction to drivably connectthe damper to the turbine runner, as a result of which the entire axiallength of this known arrangement becomes long.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide a simple and spacesaving construction for drivably connecting a damper to a turbinerunner.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a longitudinal sectional view of a lockup torque converteraccording to the present invention;

FIG. 2 is a cross sectional view of a clutch piston and an annularmounting member secured thereto;

FIG. 3 is a top plan view, only half shown, of the clutch piston asviewed from the right hand side of FIG. 2;

FIG. 4 is a sectional view taken through line A--A of FIG. 5; and

FIG. 5 is a top plan view, partly broken away, of a damper used in FIG.1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, the reference numeral 1 designates a converterhousing and the reference numeral 2 a crankshaft. A boss 3 and a driveplate 4 are concentrically secured to the end of the crankshaft 2, suchas, by means of a plurality of fasteners 5. Drive plate 4 carries at itsouter periphery of a ring gear 6. Drive plate 4 is drivably connected toa converter cover 9 concentrically by means of a plurality of fasteners8 using the corresponding number of spacers 7. A sleeve 10 is secured tothe central portion of the converter cover 9. Sleeve 10 is received inboss member 3 and thus the converter cover 9 is centered with respect tocrankshaft 2. Converter cover 9 has a cylindrical shape having a closedend wall adjacent the drive plate 4 and an open end. To the outerperiphery of the converter cover 9 adjacent the axial end defining theopen end thereof, a pump impeller 11 is secured by welding so as to becoupled with the converter cover 9. A turbine runner 12 is secured to ahub 13 at a flange thereof by rivetting. A stator 14 is situated betweenthe pump impeller 11 and the turbine runner 12 to form a torqueconverter. Stator 14 is mounted to a hollow stationary sleeve 16 througha one-way clutch 15.

The stationary sleeve 16 permits an output shaft 17, which may be atransmission input shaft, to extend therethrough with an annular spaceor play between them. Between the stationary sleeve 16 and the outputshaft 17 three spacers (bushings) 18, 19 and 20 are disposed axiallyspaced one after another to divide the annular space into two annularchambers 21 and 22. The hub 13 for the turbine runner 12 is splined tothe output shaft 17. Between the closed end wall of the converter cover9 and its adjacent axial end of the hub 13, an annular member of spacer23 is disposed to define a chamber 24. This chamber 24 communicates withthe annular chamber 22 through an axial opening 25 formed in the outputshaft 17 and through a radial opening 25a.

A generally annular clutch piston 26 is slidably mounted on the hub 13on an annular portion thereof. An annular clutch facing 27 is attachedto the adjacent surface of the clutch piston 26 to the converter cover9. When the clutch facing 27 of the clutch piston 26 engages with theadjacent surface of the end wall of the converter cover 9 uponengagement of the clutch, a chamber 28 is formed between the convertercover 9 and the clutch piston 26. This chamber 28 communicates with thechamber 24 through radial grooves 29 formed at one axial end of the hub13. Secured to the remote end wall of the clutch piston 26 is an annularmounting member 30. Within a limited space available between the innerperiphery of the turbine runner 12 and the inner periphery of the clutchpiston 26 a damper 31 is operatively connected between the clutch piston26 and the hub 13 to provide a driving connection.

Referring to FIGS. 2 and 3, the construction of the clutch piston 26 andthat of the annular mounting member 30 will be described hereinafter.The clutch piston 26 is die formed from a piece of plate metal andincludes a inner axially extending flange 26a and an outer axiallyextending, in the same direction, flange 26b. The clutch piston 26 isslidably mounted by the inner axially extending flange 26a on the hub13. The outer axially extending flange 26b is formed for reinforcementpurpose of the annular portion of the clutch piston 26 which will besubjected to difference, in pressure, upon engagement of the lock-upclutch. The annular mounting member 30 has a plurality of inner axiallyextending circumferentially spaced mounting legs 30a.

Referring to the ratio (1/t, see FIG. 2) of length (l) of the outeraxially extending flange 26b to thickness (t) thereof, it is preferablethat this ratio is from 2 to 8 for reducing the amount of bending of theclutch piston 26 under the influence of difference in pressure on theopposite sides of the clutch piston 26.

Preferably, the clutch piston 26 is axially offset to provide agenerally cylindrical shoulder portion 26d (see FIGS. 1 and 2) forreinforcement purpose. It is preferable that the ratio of length of thisshoulder portion 26d to thickness thereof is from 2 to 8.

The damper 31 includes a sleeve 32 and a flange 32a radially extendingfrom the sleeve 32. It also includes a plate assembly including a pairof plates 33 and 34 disposed on opposite sides of the flange 32a andspaced therefrom. The flange 32a and plates 33 and 34 have a pluralityof openings 32b, 33a and 34a (see FIGS. 1 and 4) and a spring 35 isdisposed in each set of these openings. The flange 32a has a pluralityof second openings 32c (see FIGS. 1 and 4). A plurality of torquetransmitting fasteners in the form of rivets 36 provide a drivingconnection between the plates 33 and 34. One of these rivets 36 extendsthrough each of the second openings 32c of the flange 32a to act as alimit stop between the flange 32a and the plates 33 and 34.

The sleeve 32 and the plates 33 and 34 have openings receiving the inneraxially extending flange 26a of the clutch piston 26, as best seen inFIG. 1. It will be noted that the damper 31 is arranged concentricallywith and above the inner axially extending flange 26a of the clutchpiston 26.

The damper 31 includes the annular mounting member 30 secured to theclutch piston 26. The flange 32a of the damper 31 has a plurality ofcircumferentially spaced outwardly opening notches 32d, one receivingeach of the mounting legs 30a of the annular mounting member 30 (seeFIGS. 1 and 4). If desired, some or all of the notches 32d may open tothe second openings 32c, as shown in FIG. 4.

The plate 34 has an annular mounting portion extending radiallyoutwardly and formed with a plurality of holes 34b as shown in FIGS. 4and 5. This annular mounting portion is contoured to conform with theshape of that portion of the outer shell 12a to which the mountingportion is secured by welding, as shown in FIG. 1. The holes 34b areformed for receiving welding material upon securing the annular mountingportion to the outer shell 12a by welding.

The remote open end of the converter housing 1 from the crankshaft 2 issecured to a pump housing 38 which in turn is secured to a pump cover 39secured to a transmission case 40 by means of fasteners 37. The pumpcover 39 extends radially from the stationary sleeve 16. Within the pumphousing 38, oil pump elements including an outer gear 41 and an innergear 42 are operatively disposed. A pump driving sleeve 43 extends intothe pump housing 38 and journalled thereby by means of a bushing 44. Thepump driving sleeve 43 permits the stationary sleeve 16 to extendtherethrough, and has one axial end drivingly connected to the pumpimpeller 11 and has an opposite end splined to the inner gear pumpelement 42. Since the pump driving sleeve 43 is spaced from thestationary sleeve 16, an annular oil passage 45 is formed between them.This passage 45 at its one end communicates with the inside of thetorque converter assembly and at an opposite end thereof communicateswith a source of torque converter operating oil via a suitable passagestructure formed in the pump cover 39.

The inside of the turbine runner 12 communicates with the annularchamber 21 by a radial passage 46 formed through the stationary sleeve16. This annular chamber 21 communicates with a pressure maintainingvalve 47 which in turn communicates with an oil cooler 48 communicatingin turn with an oil reservoir 50 via various parts 49 which requirelubrication. The annular chamber 22 communicates with a lock-up controlvalve 52 through an oil passage 51 (where the reference numerals 51a and51b designate fit-in balls). The lock-up control valve 52 has thefunction to selectively connect the oil passage 51 to the source oftorque converter operating oil or the oil reservoir 50.

The torque converter constructed thus far will operate as follows:

The rotation of the crankshaft 2 is always delivered to the pumpimpeller 11 through the drive plate 4, the fasteners 8 and the convertercover 9. The rotation of the pump impeller 11 is delivered through thepump driving sleeve 43 to the pump element inner gear 42. Thus the oilpump operates as long as the engine operates.

When the vehicle operating condition does not satisfy a predeterminedcondition in which lock-up clutch engagement is required, the lock-upcontrol valve 52 permits the oil passage 51 to communicate with thedischarge side of the source of torque converter operating oil.Meanwhile oil is supplied from the source of torque converter operatingoil to the inside of the pump impeller 11. The source of torqueconverter operating oil includes the oil pump 41, 42 and the pressureregulator valve, not shown. The oil in the inside of the torqueconverter assembly flows out of the turbine runner 12. The oildischarged from the turbine runner 12 flows through the radial passage46 and the annular chamber 21 to the pressure maintaining valve 47 thusthe pressure within the torque converter assembly being maintained at acertain level determined by the pressure maintaining valve 47. Thispressure, i.e., the pressure within the torque converter assembly, istransmitted through the lock-up control valve 52, the passages 51 and25, the chamber 24 and radial passage 29 to the clutch chamber 28. Thus,the clutch piston 26 is held disengaged from the converter cover 9 whenthe chamber 24 is pressurized.

Under this condition, the torque converter will perform its torquemultifying function because the oil maintained at the certain pressurewill transmit the torque under the reaction of the stator 14 from thepump impeller 11 to the turbine runner 12. The rotation of the turbinerunner 12 is transmitted to the output shaft 17 so that the engine powermay be delivered to the gear train of the associated transmission.

The oil after flowing through the pressure maintaining valve 47 willflow to the oil cooler 48 installed within the lower tank of theradiator. After being cooled by the oil cooler 48, the oil will bedistributed to the various parts or portions to be lubricated in thetransmission and thereafter flow back to the oil reservoir 50, i.e., theoil pan of the transmission. The oil pump including the gears 41 and 42will draw oil from this oil reservoir 50.

When the vehicle operating condition satisfies the predeterminedcondition, for example when the vehicles operates at speeds above apredetermined speed in the highest gear, the lock-up control valve 52will change over the cause the oil passage 51 to connect with the drainpassage 67 that leads to the oil reservoir 50. This connection willcause the oil within the clutch chamber 28 to be exhausted through theradial passage 29, the chamber 24, the oil passage 25, the oil passage51 and through the lock-up control valve 52 so that the clutch piston 26will be urged toward the left (viewing in FIG. 1) to engage with theconverter cover 9 under the influence of the difference in pressurecrated between the both sides of the clutch piston 26. When the clutchfacing 27 attached to the clutch piston 26 firmly engages with theconverter cover 9, the piston 26 will be directly connected to theconverter cover 9 which in turn is connected to the crankshaft 2 and thepump impeller 11 to rotate with them as a unit. The rotation of theclutch piston 26 is transmitted to the turbine runner 12 mechanicallythrough the annular mounting member 30, the legs 30a, flange 32a, thesprings 35 and the plates 33 and 34. The impact upon initiation of thetransmission of the rotational torque will be absorbed by the springs35. Thus, the damper 31 will transmit the torque while suppressing theimpact which otherwise would take place upon change in magnitude of thetorque transmitted therethrough. In this manner, the turbine runner 12is directly connected to the crankshaft 2 and the pump impeller 11through the damper 31, the clutch piston 26 and the converter cover 9.

Since the damper 31 is operatively disposed within a limited spaceavailable adjacent the inner periphery of the clutch piston 26, theproblem that a damper will not perform its designated function under theinfluence of the centrifugal force under high speed engine speeds willbe avoided.

Since the damper 31 is secured, by welding, to the outer shell 12a ofthe turbine runner 12, a driving connection between the damper 31 andthe turbine runner 12 has been greatly simplified.

What is claimed is:
 1. In a lock-up torque converter:a torque converterassembly including an output shaft, a hub receiving said output shaft toprovide a driving connection, a turbine runner with an outer shelldrivingly connected to said hub; a generally annular clutch pistonslideably mounted on said hub; a damper operatively connected betweensaid clutch piston and said turbine runner to provide a drivingconnection, said damper being located in a space adjacent the innerperiphery of said clutch piston, said damper including a mountingportion secured to said outer shell of said turbine runner; said damperincluding a sleeve and a flange radially extending from said sleeve;said damper including a plate assembly which in turn includes a pair ofplates disposed on opposite sides of said flange and spaced therefrom;said flange and said plates having a plurality of openings; and saiddamper including a spring disposed in each of said openings; and one ofsaid plates including said mounting portion which is secured to saidouter shell of said turbine runner.
 2. A lock-up torque converter asclaimed in claim 1, in whichsaid clutch piston has an inner axiallyextending flange, said clutch piston being slidably mounted by saidinner axially extending flange on said hub; and said sleeve and saidplates of said plate assembly have openings to receive said inneraxially extending flange.
 3. A lock-up torque converter as claimed inclaim 1, in whichsaid flange has a plurality of second openings saiddamper includes a plurality of torque transmitting fasteners whichfixedly interconnect said plates and which in part define part of saiddriving connection between said clutch piston and said turbine runner,one of said fasteners extending through each of said second openings toact as a limit stop between said flange portion and said plates wherebysmaller springs have been allowed to be used as said spring disposed ineach of said first-mentioned openings.
 4. A lock-up torque converter asclaimed in claim 2, in whichsaid clutch piston has an outer axiallyextending flange, the ratio of length of said outer axially extendingflange to thickness of said outer axially extending flange being withina predetermined range.
 5. A lock-up torque converter as claimed in claim4, in whichsaid predetermined range is from 2 to
 8. 6. A lock-up torqueconverter as claimed in claim 5, in whichsaid clutch piston is dished toprovide a generally cylindrical shoulder portion.
 7. In a lock-up torqueconverter:a torque converter assembly including an output shaft, a hubreceiving said output shaft to provide a driving connection, a turbinerunner with an outer shell drivingly connected to said hub; a clutchpiston having an inner axially extending flange, said clutch pistonbeing slideably mounted by said inner axially extending flange on saidhub; a damper operatively connected between said clutch piston and saidturbine runner to provide a driving connection and to allow said clutchpiston to be axially movable with respect to said damper; said damperincluding a sleeve and a flange radially extending from said sleeve;said damper including a plate assembly including a pair of platesdisposed on opposite sides of said flange and spaced therefrom, saidsleeve and said plates of said damper being disposed in a spaced andcoaxial relationship about said inner axially extending flange of saidclutch piston.
 8. A lock-up torque converter as claimed in claim 7, inwhichone of said plates of said plate assembly has a mounting portionsecured to said outer shell of said turbine runner.
 9. In a lock-uptorque converter:a torque converter assembly including an output shaft,a hub receiving said output shaft to provide a driving connection, aturbine runner with an outer shell drivingly connected to said hub; agenerally annular clutch piston slideably mounted on said hub; a damperoperatively connected between said clutch piston and said turbine runnerto provide a driving connection and to allow said clutch piston to beaxially movable with respect to said damper, said damper being locatedin a space adjacent the inner periphery of said clutch piston, saiddamper including a mounting portion secured to said outer shell of saidturbine runner; said damper including a sleeve and a flange radiallyextending from said sleeve; said damper including a plate assembly whichin turn includes a pair of plates disposed on opposite sides of saidflange and spaced therefrom; said flange and said plates having aplurality of first openings; and said damper including a spring disposedin each of said first openings; one of said plates including saidmounting portion which is secured to said outer shell of said turbinerunner; said flange having a plurality of second openings; and saiddamper including a plurality of torque transmitting fasteners whichfixedly interconnect said plates and which in part define part of saiddriving connection between said clutch piston and said turbine runner,one of said fasteners extending through each of said second openings toact as a limit stop between said flange portion and said plates wherebysmaller springs have been allowed to be used as said spring disposed ineach of said first-mentioned openings.
 10. In a lock-up converter:atorque converter assembly including an output shaft, a hub receivingsaid output shaft to provide a driving connection, a turbine runner withan outer shell drivingly connected to said hub; a clutch piston havingan inner axially extending flange, said clutch piston being slideablymounted by said inner axially extending flange on said hub; a damperoperatively connected between said clutch piston and said turbine runnerto provide a driving connection; said damper including a sleeve and aflange radially extending from said sleeve; said damper including aplate assembly including a pair of plates disposed on opposite sides ofsaid flange and spaced therefrom; said sleeve and said plates of saiddamper being disposed in a spaced and coaxial relationship about saidinner axially extending flange of said clutch piston; one of said platesof said plate assembly having a mounting portion secured to said outershell of said turbine runner; said damper including an annular mountingmember secured to said clutch piston and having a plurality of inneraxially extending circumferentially spaced mounting legs; and saidflange having a plurality of circumferentially spaced outwardly openingnotches, one receiving each of said mounting legs.
 11. In a lock-uptorque converter havinga torque converter assembly including an outputshaft, a hub drivingly connected with said output shaft and a turbinerunner having an outer shell drivingly connected to said hub, thecombination of: a damper comprising: an annular sleeve having a radialflange, said annular sleeve being disposed in a spaced coaxialrelationship about said hub, first and second annular plates disposed onopposite sides of said radial flange, said first annular plate beingsecurely fixed to said outer shell of said turbine runner, meansdefining a plurality of first apertures in said radial flange, meansdefining a plurality of second apertures in said radial flange,fasteners fixedly interconnecting said first and second plates and eachextending through one of said first apertures, and biasing means diposedbetween said first and second annular plates for biasing said first andsecond annular plates and said radial flange in first and secondrotational directions respectively; a concave dished clutch pistonslideably received on said hub and receiving said damper in theconcavity thereof; and an annular mounting member disposed in saidconcavity of said clutch piston and fixedly connected thereto, saidannular mounting member having a plurality of axial extendingcircumferentially spaced legs which are received respectively in one ofsaid second apertures of said radial flange.